Substitution-mediated enhanced adsorption of low concentration As(v) from water by mesoporous MnxFe3−xO4 microspheres. Issue 5 (27th March 2019)

• Record Type: Journal Article
• Authors: Xie, Yili; Tian, Chen; Chen, Weiyi; Wu, Can; Liu, Zhangbin; Ning, Ping; Deng, Hong; Lin, Zhang
• Is Part Of: Environmental science. Volume 6:Issue 5(2019)
• Page Start: 1406
• Page End: 1417
• Publication Date: 2019-03-27
• Subjects: Environmental sciences -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9en00064j
• Languages: English
• ISSNs: 2051-8153

Abstract

Abstract : Manganese ferrite (Mn x Fe3− x O4 ) microspheres with a spinel structure are very effective adsorbents for arsenic (As) removal. Abstract : Manganese ferrite (Mn x Fe3− x O4 ) microspheres with a spinel structure are very effective adsorbents for arsenic (As) removal. In this study, highly ordered mesoporous Mn x Fe3− x O4 has been synthesized by a facile and convenient solvothermal method. By comparing the different doping amounts of manganese (Mn), the results show that Mn1.8 Fe1.2 O4 has a relatively higher efficiency for arsenate (As(v )) removal due to the modified surface complexes caused by the optimum Mn substitution. Rietveld XRD refinement reveals that Mn1.8 Fe1.2 O4 microspheres possess the highest distribution ratio of Mn/Fe situated between the octahedral ( O h ) and the tetrahedral ( T d ) sites of the unit cell. The as-prepared Mn1.8 Fe1.2 O4 microspheres with MnO6 O h sites in Fd 3̄ m symmetry exhibit a promising ability for toxic As(v ) adsorption, which is mainly attributed to the increase of coordinated complexes. Extended X-ray absorption fine structure (EXAFS) analysis indicates that the coordination structures of As(v ) on Mn1.8 Fe1.2 O4 are present as bidentate binuclear complexes with a regular distance of As–Fe = 3.41 Å. Apart from this, As(v ) can also bind with Mn-doped sites through the monodentate coordination mode at a distance of As–Mn = 3.51 Å with a preferred coordination number (CN) of 4.4. This work discloses the correlation between the superior As(v ) adsorption ability and MnO6 O h sites in Mn1.8 Fe1.2 O4 and provides an emerging and promising method to enhance the adsorption capacity of As via modifying Mn doping sites based on the pollutant structure to achieve synergistic adsorption effects.